Brake



April 10, 1934. R, s, SANFORD BRAKE Original Filed Jan. 18, 1928 IN VENTOR. EfiA/FURQ Ray 5 Patented Apr. 10, 1934 PATENT OF FICE BRAKE Roy S.Sanford, South Bend, Ind., assignor to Bendix Brake Company, South Bend,Ind., a

corporation of Illinois Original application January 18, 1928, SerialNo. 247,505. Divided and this application December 3, 1930, Serial No.499,684

11 Claims.

This invention relates to brakes and more particularly to internalexpanding brakes.

The present invention is a division of my pending application Serial No.247,505, filed January The invention broadly comprehends an operatingmember for the friction elements of a brake arranged to apply theseelements in either forward or reverse braking with smooth action devoidof objectionable noises.

An object of the invention is to provide an anti-friction mounting forthe operating lever of a brake so that the lever may be operated withthe least possible friction.

An important object of the invention is to provide an operating meansfor the friction ele ment of a brake having an anti-friction bear ing ona fixed anchor and line contact with the separable ends of the frictionelement, so that smooth operating effects may be attained with the leastpossible friction.

Another object of the invention is to provide an operating lever for thefriction element of a brake having a compound curved cam adaptable forengagement with the separable ends of the friction element with linecontact and to fulcrum on a roller bearing supported by a fixed anchor.

An important feature of the invention is a fixed anchor havingpositioned thereon a roller bearing supporting an operating member.

Another important feature is an operating lever supported on a fixedanchor and provided with a compound curved cam adaptable for engagementwith the separable ends of the friction element with line contact.

Other objects of the invention will appear from the followingdescription taken in connection with the drawing, which forms a part ofthis specification, and in which:

Figure 1 is a sectional view of a brake taken just back of the head ofthe drum illustrating the friction elements and operating member inelevation;

Figure 2 is a section substantially on line 2-2, Figure 1; and

Figure 3 is an enlarged detail view of the operating member.

Referring to the drawing for more specific details of the invention, 10represents a fixed support such as a backing plate having associatedtherewith a rotatable drum 12. Positioned for movement on the backingplate is a friction elementcomprising a primary shoe 14 and a secondaryshoe 16 which may be of any preferred type.

As shown, the shoes 14 and 16 are interchangeable. Each shoe comprises arim 18 supported by a web 20 and a lining 22 suitably secured on the rimfor co-operation with the braking surface of the drum. The shoes 14 and16 are suitably supported on the backing plate by steady rests 24 whichmay be of anysuitable known construction, but which are preferablyarranged to retain the friction elements in any position to which theymay be shifted by the whipping action of the drum to provide under allconditions an absolute minimum clearance between the friction elementand the drum.

As shown, the articulated ends of the friction element or the shoes areconnected by an adjusting member comprising a right and left threadedscrew 26 having its respective ends threaded into suitable connectors orpivots 28 positioned for movement in transverse openings in thearticulated ends of the shoes. The screw is provided with a polygonalportion 30 adaptable for the reception of an adjusting wrench which maybe inserted through an opening 32 in the backing plate, and positionedon the screw are suitable lock nuts 34 adapted to retain the shoes inadjusted position.

Positioned between the separable ends of the friction elements 14 and 16is a fixed anchor 36. As shown, the anchor 36 is pressed into a bracketor plate 38 secured in any desirable manner to.

the backing plate 10. Positioned on the anchor 36 is a sleeve 40 andinterposed between the sleeve and the anchor is a plurality of rollers42. As shown, a sleeve 44 is fitted snugly on the anchor 36 and thissleeve is provided with a circumferential flange 46 retaining therollers 42 against endwise movement. The sleeve 46 is retained inposition by a cotter pin 48 passing diametrally through the sleeve andthe anchor.

A floating lever 50 is positioned on the anchor between the sleeve 40and the shoe 14. This lever has a semi-cylindrical bearing surface 52engaging the sleeve 40 and arranged on the lever is a cam 54 havingcompound curved engaging surfaces. These surfaces engage a wear plate 56on the shoe 14 and a thrust member or projection 56 on a wear plate 60attached to the shoe 16. The cam surfaces of the operating lever engagethe wear plate 52 and thrust member 54 with line contact, so thatfriction between these parts is reduced to a minimum. Thesemi-cylindrical portion 52 of the operating lever 50 is adapted torock, together with the sleeve 40, on the roller bearings 42. Hence,friction between these parts is nil or negligible.

As shown, the flange 46 on the sleeve 44 is extended to overlie the camso that lateral movement of the operating lever 50 is avoided. Theoperating lever is connected by an operating cable 62 extending throughthe backing plate 10 to a suitable source of power, not shown, andconnected between the shoes is the conventional return spring 64:adapted to return the shoes to the idle position.

In operation, force is applied to the lever 50 to rock the lever on theanti-friction rollers 42, and upon rocking the lever from its idleposition, the separable ends of the shoes 14 and 16 are spread to engagethe shoes with the braking surface of the drum. This movement of theshoes is accomplished through the compound curved engaging surfaces onthe lever engaging the separable ends of the shoes 14 and 16. Theengagement between the shoes and the compound curved surfaces is that ofline contact. Hence, friction between these elements is reduced to aminimum.

The invention not only provides means for applying the friction elementsto the braking surface of the drum with as little friction as ispossible, but also provides means for applying these elements with asmooth operating effect devoid of objectionable noises.

Although this invention has been described in connection with certainspecific embodiments, the principles involved are susceptible ofnumerous other applications that will readily occur to persons skilledin the art. The invention is, therefore, to be limited only as indicatedby the scope of the appended claims.

Having thus described the various features of the invention, what Iclaim as new and desire to secure by Letters Patent is:

l. A brake comprising a fixed anchor, an antifriction bearing on theanchor and a floating lever having one end engaging the anchor.

2. A brake comprising a fixed anchor, an anti friction member positionedon the anchor and a lever having one end supported on the antifrictionmember.

3. A brake comprising a floating friction device having separable ends,an anchor positioned between the ends, an anti-friction member on theanchor and an applying lever on the friction member having a portioncurved to engage one of the separable ends and to clear the anchor andengage the other separable end.

4. A brake comprising a fixed support, a floating friction elementhaving separable ends and positioned for movement on the support, afixed anchor on the support between the separable ends of the frictionelement, an anti-friction member on the anchor and a lever on the anchorhaving a reversed curved surface engaging the separable ends of thefriction element by line contact.

5. A brake comprising a fixed support, a rotatable drum associatedtherewith, a friction element on the support having separable ends, ananchor on the fixed support between the separable ends of the frictionelement, an anti-friction bearing on the anchor, a floating lever havingone end supported by the bearing and means on the floating leverengaging the respective separable ends of the friction element.

6. A brake comprising a drum, a fixed anchor adjacent the drum, a sleevesurrounding the anchor in spaced relation thereto, a series ofanti-friction rollers in the space between the anchor and the sleeve anda friction device having a radial surface in anchoring engagement withthe sleeve.

7. A brake comprising a drum, a fixed anchor adjacent the drum, a sleevesurrounding the drum in spaced relation thereto, a series ofanti-friction rollers in the space between the anchor and the sleeve anda floating friction device anchoring at one end against the sleeve whenthe drum is turning in one direction and anchoring at the other endagainst said sleeve when the drum is turning in the other direction.

8. A brake comprising an anchor, a bearing on the anchor, an operatingmember co-operating therewith and means on the anchor positivelyretaining the operating member and the bearing against displacement.

9. A brake comprising a fixed support, an anchor on the support, abearing on the anchor including a series of anti-friction members, and afriction element engaging the anchor through the anti-friction bearing.

10. A brake comprising a fixed support, an anchor on the support, ananti-friction bearing including a series of rollers surrounding theanchor, and a friction element co-operating with the anchor through saidbearing.

11. A brake comprising a fixed support, an anchor on the support, afriction element co-operating therewith, an operating member for thefriction element and a member sleeved on the anchor retaining thefriction element and operating member against displacement.

ROY S. SANFORD.

